let str = 'boder-bottom-case'
Array.from(str)
let arr = []
for (let i = 0; i < str.length; i++) {
    arr.push(str[i])
    if (str[i-1] == '-') {
        arr[i] = str[i].toUpperCase()
    }
}
let s = arr.join('').split(',').toString()
console.log(s.split('-').join(''));